2022 Fiscal Year Final Research Report
Exploring for subduction-derived carbon in mantle wedges
| Project/Area Number |
20H02000
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Review Section |
Basic Section 17040:Solid earth sciences-related
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| Research Institution | Kyushu University |
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Principal Investigator |
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| Co-Investigator(Kenkyū-buntansha) |
吉村 俊平 北海道大学, 理学研究院, 助教 (20706436)
馬上 謙一 北海道大学, 理学研究院, 助教 (70624758)
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| Project Period (FY) |
2020-04-01 – 2023-03-31
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| Keywords | マントルウェッジ / 炭素 / 流体包有物 / 同位体比 |
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| Outline of Final Research Achievements |
In this study, we analyzed isotope ratios of carbon and nitrogen in fluid inclusions in mantle wedge-derived peridotite xenoliths to explore the presence of oceanic plate-derived carbon in the mantle wedge. The isotope ratios were measured using a combination of a gas extraction system for fluid inclusions in an ultra-high vacuum and a conventional mass spectrometer, as well as mass spectrometric analysis by micro-Raman spectroscopy. Carbon and nitrogen isotope ratios were measured for a total of 10 peridotite samples collected from subduction zones in the Ichinomegata in Oga, Akita Prefecture, Japan, and in Far Eastern Russia. The resulting isotopic signatures were interpreted to be derived from deep seawater.
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| Free Research Field |
地球システム化学
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| Academic Significance and Societal Importance of the Research Achievements |
本研究では，海洋プレートから由来した炭素がマントルウェッジに浸入していることを世界で初めて直接証明することに成功した．これは，沈み込む海洋プレートと火山噴火を出口・入口とする大規模な炭素循環系の存在を示すものであり，社会的にも関心が高い炭素循環系の時空間スケールや炭素流量の探求に極めて大きな影響を及ぼすに違いない．また，マントルに含まれる炭素はマントル鉱物の融点を低下させ，沈み込み帯におけるマグマ生成機構にも影響をもたらすため，本研究の結果は，地球内部と地球表層をつなぐ熱や物質の循環系全体の枠組みに再構築を迫る知見になると思われる．
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